mDNSResponder Constantly Doing "Something"

I noticed my mDNSResponder connecting constantly to opendns (didn't always happen but when it did it was constant). Found the links below. It basically requires a bit of under-the-hood tweaking.

1. Make a back up copy of the mDNSResponder.plist file as a precaution.
2. Open the mDNSResponder.plist file in Terminal using your preferred text editor. Here is a sample command:
   

   sudo nano "/System/Library/LaunchDaemons/com.apple.mDNSResponder.plist" 
   

3. Add "<string>-NoMulticastAdvertisements</string>" to the array in the "ProgramArguments" section.
   
   In other words:
   

     <key>ProgramArguments</key>
           <array>
               <string>/usr/sbin/mDNSResponder</string>
               <string>-launchd</string>
           </array>    
   

   becomes...
   

           <key>ProgramArguments</key>
           <array>
               <string>/usr/sbin/mDNSResponder</string>
               <string>-launchd</string>
          <string>-NoMulticastAdvertisements</string>
     </array>
   

4. Save the file.
   
   Important: If you edited the file using emacs, you must remove the emacs backup file (the file with a tilde at the end of the name, "/System/Library/LaunchDaemons/com.apple.mDNSResponder.plist~") or your Mac will not start up.
   
5. Restart your Mac.

****

UPDATE 12 June 2010: The problem, as it turns out, was listing my OpenDNS servers in both my Airport Extreme (for the entire home network) and my Mac Pro. As soon as I deleted the OpenDNS servers from Network Preferences on my Mac Pro, everything returned to normal...no more constant outgoing connections. The above method worked too, but it was at the cost of losing Bonjour connectivity on my home network (not acceptable).

[From Snow Leopard disabling mDNSResponder/Bonjour drops internet - Mac Forums]

Mac OS X v10.6 uses the mDNSResponder process for unicast DNS (Domain Name System) functions, as well as Bonjour functions. Disabling the mDNSResponder process will also disable unicast DNS resolution, and without unicast DNS resolution, Mac OS X v10.6 cannot resolve hostnames such as www.apple.com.

In some network environments, administrators may prefer that Mac OS X v10.6 not transmit Bonjour service advertisements. You can use this advanced article if you are a network administrator who needs to disable Bonjour advertising service without disabling Bonjour queries and DNS.

[From Mac OS X v10.6: Disabling mDNSResponder will disable DNS]

User accounts and file sharing in Leopard

Computerworld - User accounts and file sharing in Leopard: What's new:

NetInfo is no more, and you can now create groups and share any folder on your Mac.

Apple has made some major improvements in Leopard when it comes to creating and managing user accounts, file sharing and remote access. The biggest change, though, is something most Macintosh users may never see because it was accomplished so seamlessly: Apple has retired the proprietary NetInfo database that has stored and managed local accounts since the beginning of Mac OS X.

Bonjour suddenly M.I.A. (no network machines)

If you click on the Network icon in your left sidebar and do not see your other machines (if you have a local network), try restarting all the machines first. Next, disable and re-enable file sharing via System Prefs Sharing prefpane. This might get Bonjour back to snooping your network the way Apple intended.

The Mysterious Library Alias

Many of you in Tiger may have noticed the problem discussed here.

Specifically, a new generic file alias shows up in under Network in the Finder. Apparently it has something to do with NFS. A user on the above forum wrote:

The network Library contains items that are available to all users on your network. It has been around since at least 10.1. You would only use this folder if you part of a network being managed with OS X Server.

From Mac OS X Server Administrator’s Guide:

"Adding System Resources to the Network Library Folder

This Library folder in the Network globe is included in the system search path. This gives you the ability to make available, from the network, any type of system resource that resides in the local Library folder. These resources could include fonts, application preferences, ColorSync profiles, desktop pictures, and so forth. Mac OS X accesses the network Library folder before the local Library folder, so network resources with the same name take precedence. You can use this capability to customize your managed client environment."

So just ignore it. It represents network services that aren't available to you.

Anyway, the important point is how to fix it from another user:

>>>When I click on the Network icon in the Sidebar the window shows "Servers" and an alias called Library. If I click on it the system tells me the alias is broken. I don't know what this file is for.

I deleted the file but I had to log in as root to do it. After that I could login to and user on my Mac and the file was gone. After I did a restart it came back again. Anybody know what this file is?<<<

To prevent it from comming back, edit "/System/Library/StartupItems/NFS/NFS" and place a # in front of the line:

ln -s /automount/Library /Network/Library

As shown below....

nfsd ${arguments}
fi
##
# Start the automounter
##
if [ "${AUTOMOUNT:=-YES-}" = "-YES-" ]; then
automount -m /Network -nsl -mnt ${AUTOMOUNTDIR}
# ln -s /automount/Library /Network/Library
automount -m /automount/Servers -fstab -mnt /private/Network/Servers -m /automount/static -static -mnt
${AUTOMOUNTDIR}
ln -s /automount/Servers /Network/Servers
#
# Hint that the name /Network should be localized:
#
ln -s . /Network/.localized
fi
#
# Leave a mark upon completion of the automounter startup: